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AirHistory

Unhealthy (101+) AQI Cities

0 US cities have a 5-year average AQI in the unhealthy range. Air quality is unhealthy for sensitive groups and may affect the general population.

0
Cities
0.0%
Of All Cities
0
Improving
0
Worsening

All Unhealthy AQI Cities

CityState5yr Avg AQIGradeTrendWorst Pollutant

Frequently Asked Questions

Air quality is unhealthy for sensitive groups and may affect the general population. The AQI (Air Quality Index) is a standardized EPA measure from 0-500 that communicates daily air quality levels.

0 of 1,020 monitored US cities have a 5-year average AQI in the unhealthy range (101-500).

When AQI exceeds 100, sensitive groups should limit outdoor activity. Above 150, everyone should reduce prolonged outdoor exertion. Stay indoors with windows closed, use air purifiers, and check daily AQI forecasts on AirNow.gov.

Sources: EPA Air Quality System (AQS)
Last updated:

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